The Effect of an Air Bubble in the Anterior Chamber on the Change in Intraocular Pressure (IOP)
Amir Samsudin *
Department of Ophthalmology, University of Malaya, Kuala Lumpur, Malaysia and UCL Department of Mechanical Engineering, London, United Kingdom and NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
Ian Eames
UCL Department of Mechanical Engineering, London, United Kingdom
Steve Brocchini
NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom and UCL School of Pharmacy, London, United Kingdom
Peng Tee Khaw
NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
*Author to whom correspondence should be addressed.
Abstract
Purpose: To compare rate of change in IOP with and without air bubbles in the anterior chamber (AC).
Methods: Enucleated porcine eyes were infused with Balanced Salt Solution (BSS) at 10μl/min. In one experiment, 5 eyes each were injected with 0.15 or 0.30ml bubbles without prior removal of aqueous humour while 5 controls were not injected. In another experiment, 9 eyes were injected with 0.30ml bubbles with prior removal of 0.30ml aqueous humour while 8 controls were not injected. The rate of change in IOP from 5mmHg to 20mmHg was compared. Statistical analysis involved the unpaired t-test and one–way ANOVA. P<.05 was considered statistically significant.
Results: In the first experiment, after initial spikes IOP settled to +3.5+/-3.4mmHg and +4.7+/-5.1mmHg from the original baseline with 0.15ml and 0.30ml respectively (P=.13). The rate of change was 0.25+/-0.09mmHg/min for controls, 0.31+/-0.12mmHg/min for 0.15ml and 0.46+/-0.10mmHg/min for 0.30ml. The difference between the control and 0.30ml groups was significant (P=.02). In the second experiment, IOP after injection was 5.3+/-1.6mmHg compared to 5.9+/-0.7mmHg in the control group (P=.30). The rate of change in IOP was 0.28+/-0.09mmHg/min with bubbles and 0.30+/-0.08mmHg/min without (P=.68).
Conclusion: An air bubble in the AC does not affect the rate of increase in IOP.
Keywords: Aqueous humour, anterior chamber, intraocular pressure, IOP, trabeculectomy, glaucoma